Definition from Wiktionary, the free dictionary
fireship (plural fireships)
- (nautical) A sailing ship that has been set alight and left to drift into an opposing fleet. Famously used by Englishman Sir Francis Drake when fighting the Spanish Armada of 1588.
- (vulgar, slang) A diseased prostitute.
Related terms 
- Depraved and Insulting English – Peter Novobatsky & Ammon Shea ISBN: 0-15-601149-2